Combustion air preheating and admitting means for furnaces



March 17, 1953 BARNETT 2,631,554

COMBUSTION AIR PREHEATING AND ADMITTING MEANS FOR FURNACES Filed Aug. 15, 1947 3 Sheets-Sheet 1 FIG. I.

Inventor A ltomeys March 17, 1953 BARNETT 2,631,554

COMBUSTION AIR PREHEATING AND ADMITTING MEANS FOR FURNACES Filed Aug. 13, 1947 3 Sheets-Sheet 2 Inventor A Home y S L. COMBUSTION March 17 1953 BARNETT 2,631,554

AIR PREHEATING AND ADMITTING MEANS FOR FURNACES 3 Sheets-Sheet 3 Filed Aug. 15, 1947 I y 22M. w

m 1 3 .MN. 3 N n 2 .i a V w7///,/,//// a 4 72m?- IwJiAJJ m i OI; wing: W11 2 I 11 113" ":30 w w n n n n w n u n n u u I l i: u T- H; 1 I: :1 V .y n I "C L mm mm m mm a m N N w N Patented Mar. 17, 1953 GOMBUSTION AIR. PnEHn-A'rmGANnAm MITTING MEANS FOR FURNACES LeonardBarnett, Leeds, England Application August 13, 1947,.Seria1No. 768,461?

' In Great Britain November 18,1943

Section 1'; Public Law 690; August; 8, 1946 v Patent'iexpires Novemb,er:18, 1963;

and in particular to the crown and cheek baflies such as are placed adjacent the fire-door on the insideof" the boiler front todefiect the hot gases within" the boiler and the invention has for its chief object to provide a construction or modification of bafiie to replace the ordinary plain .baflles, and one which will enable soot formation and smoke to be considerably reduced or prevented thereby saving fuel.

Preheaters for air have been proposed cap-able of being attached to the existing wall or boiler front or to the innerside of the firebox door, or inserted Well inside the furnace and comprising a hollow body adapted to be heated by the fire in the furnace and constructed so that some air on its way to the furnace may be preheated prior to passing into the furnace. Such preheaters have been provided with an inlet means to admit air from the exterior of the furnace into the hollow body through which the air traverse to be discharged through a plurality of holes directing the air over the burning fuel within the furnace.

According to the invention a combined baflie and air inlet is provided comprising a self contained casing or unit capable of being substituted for existing crown or cheek bafiles of the furnace, and through which a stream or streams of preheated air is introduced to the furnace by way of a valve having its air inlet being regulated to control the flow of air to and through the'baffle and air inlet.

order that the invention may be clearly understood and readily carried into effect the same will now be more fully described with reference to and by the aid of the accompanying drawings, wherein:

Figure 1 is a front elevation or exterior view of a crown baffle with the air admission valve removed.

Figure 2 is an interior view showing the labyrinth for the passage of air.

Figure 3 is a rear view of a crown baflie.

Figures 4 and 5 illustrate a sectional elevation and an isometric view respectively of constructlon of the valve for fitting to the crown baflle.

Figure 6 is a part sectional plan view showing the crown baffle air distributor structure and air admission valve secured to the boiler furnace.

Referring to the drawings, the baflle takes the form of a chamber I drilled or tapped at 2 on its front or outer face 3 at a point towards the apex or crown of the baflle. Said drilled or tapped opening 2 will constitute an air inlet fitted with an extension tube I9 which fits into and is secured by means ofa set screw 22 to a tube IE5, whichis part of a hollow casting I3 which has air inlets I 4 adjacent the hot surfac of the boiler front 21 and warmed air passes from adjacent, the. boiler front. 2|, through, the air. inlet M into the tubes I5 and I9 and into the chamber I.

The interior of the .baffie or the chamber I is provided with a staggered arrangement of approximately vertically disposed ribs 6 (see Figure 2) adapted to afford a labyrinth and cause the air admitted to pass through a tortuous path, within the chamber. The arrangement is such that the air entering the tube I9 will be conducted to the sides of the baflle then upwardly to a series of jets I disposed along or near the upper edge 8 of the bafile and thereby direct hot air currents into the furnace. The jets will preferably be designed to direct the streams of hot air downwardly on to the fire or fuel in the furnace.

The tube I5 has a butterfly valve It con-trolled by an arm II, which worlos in conjunction with notches I8, which determine the position of the valve I6. The hollow casting I3 and its extension tube I9 will be held in position in the inlet 2, by means of the locknut .20 and the front and rear plates II, I2 of the baffle or air distribution unit are secured together by screws '2 3, see Figure 6, whilst the complete baffle or air distribution unit is secured to the boiler or furnace front 21 by means of the bolts '24 above the fire door 25.

With this arrangement the air admitted through the valve or damper controlled inlet 2 will be preheated by coming into contact with the front of the furnace 2| to which the bafile is applied prior to entering the valve through the inlets I4. Further heating of the air is encountered in its passage through the labyrinth afforded by the staggered arrangement of the ribs or baflles 6 in the chamber.

.The baflle will preferably comprise front and rear plates II, I2 respectively with the upper set of ribs 6 formed on the plate I2 which may alternate with similar ribs on the bottom of the chamber I in such a way that the air from the inlet valve or damper controlled inlet is conducted through the passage aiforded by the cooperating ribs towards the ends of the bafiie where it rises and passes to the jets 1 at the upper part of the bafll-e to be directed down on to the fuel or firebed in the furnace.

If desired instead of passing air through the 'bafiie from the atmosphere, it may be induced or blown through the chamber or hollow casting by means of existing forced draught equipment with or without the requisite alterations .to the valve control mechanism.

[[claim:

1. In combination with a boiler furnace, a hollo w casing positioned within said furnace adjacent the fire door of said furnace, said casing comprising an outer wall having an air inlet opening therein, an inner wall having air jet' openings therein, and internal ribs defining a tortuous path of communication between said air inlet opening and said air jet openings, an air inlet tube in communication with said air inlet,

opening and extending to the exterior of said furnace, and air valve means at the outer end of said air inlet tube, said valve means including a hollow collecting member connected to the outer end of said tube and provided with air inlets disposed on opposite sides thereof, said air inlets facing the furnace and positioned adjacent thereto so that the air is preheated prior to being introduced into the collecting chamber and the tube, and a butterfly valve in said tube adjacent said member for controlling the flow of the heated gases into the tube.

2. Apparatus according to claim 1 wherein said 4. hollow collecting member comprises a central hub extending outwardly therefrom and connected to and enclosing the outer end of said air inlet tube, said air inlets being adjacent said hub, and the butterfly valve being positioned within said hub for adj ustably controlling the flow of the air into the tube.

LEONARD BARNETT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 617,354 Reed Jan. 10, 1899 7 711,653 Burdick Oct. 21, 1902 1,464,299 Swahtz Aug. 7, 1923 1,556,916 Craig Oct. 13, 1925 1,594,302 Kennedy July 27, 1926 FOREIGN PATENTS Number Country Date 99,447 Switzerland July 23, 1940 542,186 Great Britain. DecJBO, 1941 

